There is a vast diversity of historic heirloom apple varieties around the world. Apples of various colors, sizes, tastes, uses, and ripening times can be found. In Slovakia, there has recently been a rising interest to preserve these apple varieties. The life of a tree is partially influenced by the growing conditions of the environment where the tree grows. In this paper, macroscopic and microscopic characteristics of four selected heirloom apple trees growing in Slovakia’s Štiavnické vrchy were observed. Studying the microscopic structure of historical heirloom apple trees wood could reveal specific cell arrangements of tissues. This could help to specify the individual varieties.

Gap dynamics are driving many important processes in the development of temperate forest ecosystems. What remains largely unknown is how often the regeneration processes initialized by endogenous mortality of dominant and co-dominant canopy trees take place. We conducted a study in the high mountain forests of the Central Western Carpathians, naturally dominated by the Norway spruce. Based on the repeated forest inventories in two localities, we quantified the structure and amount of deadwood, as well as the associated mortality of standing dead canopy trees. We determined the basic specific gravity of wood and anatomical changes in the initial phase of wood decomposition. The approach for estimating the rate of gap formation and the number of canopy trees per unit area needed for intentional gap formation was formulated based on residence time analysis of three localities. The initial phase of gap formation (standing dead tree in the first decay class) had a narrow range of residence values, with a 90–95% probability that gap age was less than 10 or 13 years. Correspondingly, a relatively constant absolute number of 12 and 13 canopy spruce trees per hectare died standing in 10 years, with a mean diameter reaching 50–58 cm. Maximum diameters trees (70–80 cm) were represented by 1–4 stems per hectare. The values of the wood-specific gravity of standing trees were around 0.370–0.380 g.cm⁻³, and varied from 0.302 to 0.523 g.cm⁻³. Microscopically, our results point out that gap formation is a continuous long-lasting process, starting while canopy trees are living. We observed early signs of wood degradation and bacteria, possibly associated with bark beetles, that induce a strong effect when attacking living trees with vigorous defenses. New information about the initial phase of gap formation has provided a basis for the objective proposal of intervals and intensities of interventions, designed to promote a diversified structure and the long-term ecological stability of the mountain spruce stands in changing climate conditions.

False heartwood is a common defect in beech wood. If the false heartwood is healthy and without microbial attacks, it is possible to utilize such material. Application of adhesives and coatings is an important part of the wood furniture industry. Studying wood surface properties provides answers to problems in application of glues, coating materials, and similar. Comparing wettability and surface free energy of false heartwood, ripe wood, and sapwood zones of beech was the focus of this paper. Two-way ANOVA with Duncan post-hoc test of multiple comparison was used for testing of the hypotheses and statistical evaluation of the results. The zones were also examined with light microscopy. Two testing liquids were used in wettability experiment – redistilled water and diiodomethane. Ripe wood showed the best wettability for both testing liquids among the wood zones. Significant differences in contact angles at the beginning of the wetting process, equilibrium contact angles, and surface free energies were found in almost all pairwise comparisons of the wood zone and testing liquid factors. The pairs where significant difference was not found were as follows: false heartwood and ripe wood in testing with redistilled water, and ripe wood and sapwood in testing with diiodomethane. Equilibrium times in all wood zones for both testing liquids were also statistically evaluated. Significant differences were found in all wood zones in testing with redistilled water. In testing with diiodomethane, equilibrium time for false heartwood was significantly different from ripe and sapwood zone equilibrium times.

The steaming of wood changes its physical, mechanical and chemical properties in a complex way. The information about the wettability, surface free energy, and Janka hardness of steamed beech false heartwood and sapwood is not sufficient; these properties were therefore the main focus of this article. Wettability was determined by contact angle measurement with standard testing liquids. The steaming regime was a significant factor for wetting with redistilled water, and it had a mutual interaction during wetting with diiodomethane along with the factor wood zone. The steaming regimes also significantly influenced the surface free energy of the beech wood. According to the contact angles and surface free energy values, the Mode I steaming regime showed a better wettability than the Mode II regime. Analysis of the Janka hardness values showed that wood zone, steaming regime and anatomical direction significantly influenced the hardness in a mutual interaction. Beech wood steamed with the Mode I steaming regime showed a significantly lower Janka hardness in all anatomical directions; the Mode II steaming regime showed a significantly lower hardness only in the cross directions. The statistical difference between false heartwood and sapwood hardness was not significant only in the tangential direction for both steaming regimes and untreated wood.

Development of new materials puts a great emphasis on saving production costs, energy, decreasing the amount and number of chemicals used during the manufacturing process. Bio-based materials can be ecologically produced and recycled after their lifespan, which saves the environment. The recent interest in bio-based materials led to the objective of this work. In this article, the structure of spruce wood (Picea abies) biodegraded by the white-rot fungus Trametes versicolor and brown-rot fungus Gloeophyllum trabeum was studied. Structure of the wood was observed macroscopically and microscopically. Classic and unusual stain combinations were used in this work. Ethanol was intentionally omitted in the process of making permanent mounts. It was done to preserve the coherence of the decayed microsections and to keep small fragments from being rinsed away. Results of the observations suggest that spruce wood decayed by these fungi could be used as an insulation material. Wood decaying fungi decrease the density of wood and increase its porosity. A low density and high porosity are important properties for insulation materials. According to the results, spruce wood decayed by Trametes versicolor would be more suitable to be used as an insulating material.